The p53 codon 72 Proline allele is associated with p53 gene mutations in non-small cell lung cancer

The p53 gene plays a critical role in cell cycle control, the initiation of apoptosis, and in DNA repair. An Arg/Pro polymorphism at codon 72 of the p53 gene alters the ability of the p53 protein to induce apoptosis, influences the behavior of mutant p53, decreases DNA repair capacity, and may be linked with an increased risk of lung cancer. To further define the role of the p53 codon 72 polymorphism on DNA repair, lung cancer risk, and mutant p53 function, we examined the effect of this polymorphism on mutation of the p53 gene and patient survival in non - small cell lung cancer (NSCLC). Tumor and nonneoplastic (lung or lymphocyte) samples were collected from 182 patients with NSCLC. p53 mutations were detected by direct sequencing and/or the GeneChip p53 assay in 93 of 182 (51%) tumors. p53 codon 72 polymorphisms were identified by PCR/RFLP analysis. p53 mutations were significantly (P = 0.01) associated with the number of codon 72 Pro alleles: Pro/Pro homozygotes, 17 of 26 (65%); Arg/Pro heterozygotes, 45 of 79 (57%); and Arg/Arg homozygotes, 31 of 77 (40%). The number of codon 72 Pro alleles was independently associated with p53 mutations (odds ratio, 1.97; 95% confidence interval, 1.14-3.40; P = 0.01) in a multiple logistic regression model. The codon 72 polymorphism did not influence patient survival in either the entire patient group or among patients with p53 mutant tumors. In summary, the p53 Pro allele is associated with an increased frequency of p53 mutations in NSCLC.